What to eat when suffering from acid reflux dapoxetine belongs to a class of selective serotonin reuptake inhibitors (SSRIs). This short-acting inhibitor is used to treat premature ejaculation in men. The recommended dose of Cialis is 20 mg it should be taken at least 16 minutes before the sexual activity. The effect persists for 36 hours. Take Cialis once daily and do not exceed the recommended dose.